The present invention relates to a push button switch device wherein a switch element switched on or off by a downward pressing operation of a push button section is shifted from the center of the push button section toward one end thereof. Particularly, the invention relates to a push button switch device applicable to a case, for example, where an interior of a switch case is illuminated to indicate an operation state of the switch device.
The push button switch device applied to the case where the operation state thereof is indicated by the illumination of the interior of the switch case is conventionally arranged as shown in FIG. 12, for example. As shown in FIG. 12, a switch case 1 is provided with a printed wiring board 3 on a lower side thereof. A light emitting diode (hereinafter, referred to as “LED”) 5 is mounted on an upper face of the printed wiring board 3. A reflector 7 having a reflection surface defining a periphery shaped like a truncated cone for upward reflection of light from the LED 5 is disposed in the switch case 1 along with the LED 5 and is located substantially centrally of the case. A built-in switch 9 comprising a tact switch, for example, is mounted on the printed wiring board 3 at place rightward of the reflector 7.
An operation body 13 having a push button 11 removably attached thereto is disposed to close an upper side of the switch case 1. The operation body 13 is bodily pressed down by pressing down on the push button 11. The depressed operation body 13 presses down a switch portion 9a on an upper side of the built-in switch 9 via a flexible rubber body 15 whereby the built-in switch 9 is turned on.
A left end 13a of the operation body 13 is seated on a step section 17 at a left end of the switch case 1 so as to be locked to a lower face of a locking projection 19 at an upper left end of the switch case 1. On the other hand, a hook portion 13b integrally extending downwardly from a lower face of a right end of the operation body 13 is removably engaged with a lower face of an engaging portion 21 formed at a right end of the switch case 1 and having an L-shape in section.
An upward urging force derived from the elasticity of the rubber body 15 is applied to the operation body 13. When the operation body 13 is pressed down against the urging force by pressing down the push button 11, the hook portion 13b at the right end of the operation body 13 is rotated downward about the left end 13a of the operation body 13, as indicated by an arrow in FIG. 12. The left end 13a of the operation body functions as a support point. Hence, a lower side of the right end of the operation body 13 presses on the rubber body 15 to push down the switch portion 9a of the built-in switch 9 whereby the built-in switch 9 is turned on.
When the push button 11 is released from the pressing operation, the hook portion 13b at the right end of the operation body 13 rotates upward due to the elasticity of the rubber body 15. Hence, the hook portion 13b at the right end of the operation body 13 is re-engaged with the engaging portion 21 of the switch case 1 so that the operation body 13 is returned to the initial state.
It is noted that the urging force may also be applied to the operation body 13 by any other urging means than the rubber body 15. The urging means is exemplified by a spring and the like.
Another example of such a push button switch device is designed to operate as follows. When the push button is pressed down, a first end of the push button abuts against a contact member while a second end of the push button is rotated about the first end thereof, as a support point, so as to operate the switch (see, for example, Patent Document 1).
Still another example of the push button switch device is designed as follows. A push button body is provided with a pair of support shafts on a lower side thereof. A double-folded spring member is locked to these support shafts such that a folded portion of the spring member may pressingly operate the switch. The push button body, whatever part of which is pressed down, can be moved down as rotated about a support point defined by a part of the folded portion of the spring member (see, for example, Patent Document 2).    Patent Document 1: Japanese Unexamined Patent Publication No. 2004-119238 (Paragraph 0012, FIG. 2)    Patent Document 2: Japanese Unexamined Patent Publication No. H5 (1993)-266754 (Paragraphs 0022, 0023, 0026, FIG. 8, FIG. 9)